Circuit interrupter



Feb. 21, 1956 R. P. SANT CIRCUIT INTEIRRUPTER 2 Sheets-Sheet 1 FiledApril 6, 1955 INVENTOR. h 5a Feb. 21, 1956 s NT 2,735,911

CIRCUIT INTERRUPTER Filed April 6, 1955 2 Sheets-Sheet 2 INVENTOR.

United States Patent CIRCUIT INTERRUPTER Ralph P. Sant, South Milwaukee,Wis., assignor to McGraw Electric Company, Milwaukee, Wrs., acorporation of Delaware Application April 6, 1953, Serial No. 347,044

2 Claims. c1.200-117 This invention relates to a fuse construction andin particular to a throw out attachment for a mechanical fuse linkbreaker.

There are frequent occasions when it is desirable to open a fuse cutoutmanually either to inspect the cutout or to sectionalize some electricalequipment that the cutout protects. Numerous cutouts have been designedfor this purpose, one notable design being the one disclosed in U. S.Patent 2,3l0,466, issued to William O. Schultz and Alwin G. Steinmayerand assigned to the same assignee as this application. There are otherfuse cutouts with manual means for opening them under small loads.However, these are not operable with loads of 75 to 100 amperes. Theaction is not fast or strong enough to disconnect the cable effectively.

A manual opening device must operate with mechanical decisiveness sothat no failure is involved. A stumbling action would incur a falteringresponse. With electrical circuits, if the break is not quick andcomplete, arcing will result which can be very destructive or evendisastrous.

The object of this invention is to provide a means for making a cleanswift break of the fuse link in any kind of Weather condition.

Another object of this invention is to prevent arcing by positioning thelever of the fuse breaking means a distance from the upper terminal andto move it even farther away from the upper terminal with the fusebreaking movement.

A further object of this invention is to combine a flip out device withthe lever of the fuse breaking means, to accelerate the movement of theleader out of the fuse tube.

And another object of this invention is to provide a fuse breakingdevice that will apply maximum force in expelling the leader from thefuse tube.

Other objects will appear from time to time in the course of thespecification and claims.

This invention is designed to provide a novel form of fuse constructionin which the automotive functioning of the fuse under overload ispreserved and at the same time means are provided whereby the circuitmay be manually opened under load and to so construct the device thatthe arc is confined within the fuse tube whether the fuse is severedautomatically or manually and so that the expulsive action in eithercase is employed to quickly extinguish the arc and permit interruptionof the circuit with perfect safety.

I illustrate my invention in the accompanying drawings in Which:

Fig. 1 is a side elevation with parts broken away, of a fuse cutoutincorporating my fuse break lever.

Fig. 2 is a sectional view of the fuse break lever in closed position.

Fig. 3 is a sectional view of the fuse break lever in open position.

Like reference characters indicate like parts throughout.

Referring to Fig. 1, I illustrate my fuse break lever 1 incorporated inthe lower portion of a mechanical fuse cutout 2. The fuse cutout 2 ismounted upon opposite ends of an insulator 3, the center part of whichis supported by means of the clamp 4 or any suitable member from anydesired support. Or if desired, the upper and lower stationary contactscan be carried by separate insulators. The upper contact comprises ahousing 5 which is provided with a suitable connector 6 by means ofwhich a line wire may be attached, and this housing 5 is equipped with aspring pressed latch 7 which normally fits over the tip or pin 8 of theremovable cap 9 of a fuse tube 10. The fuse tube is an expulsion typefuse tube and is open at the lower end. The lower end of the tube 10 isprovided with a downwardly extending arm 11. The arm 11 is provided witha collar portion 12 which is securely attached to the fuse tube. Thedownwardly extending arm 11 has an expanded skirt portion 13 providedwith trunnions 14 on the outer sides thereof which fit within hookshaped brackets or supports 15 of the lower contract 16. The lowerstationary contact 16 is provided with a connector 19. The upper andlower contacts are secured to the upper and lower ends of the insulator3 in any suitable manner as by means of the clamping bracketsillustrated.

The upper end of the fuse tube may be provided with an eyelet 20 whichis pivoted at 21 and provided with rearwardly projecting arms 22 adaptedto lift the spring pressed latch 7 when it is desired to manually rockthe fuse tube outwardly. Preferably an upper contact spring providedwith a pair of arms 23 is provided, the contact arms 23 bearingdownwardly on the cap 9 and the contact arms 23 and the latch 7 havingupwardly turned cam portions to facilitate the rocking of the fuse backinto position after having been refused.

The fuse tube 10 is made of a fibre material and has a conductor cablewith a fusible portion extending longitudinally through it, then throughthe fuse break lever 1 and to the outer side of the fuse tube where itis secured to the fuse tube by a knurled nut on the opposite side fromthe side shown in Fig. 1. Figs. 2 and 3 show an enlarged section of thelower end of the fuse tube and cable in relationship with my fuse breakdevice.

The fuse break device 1 pivots at 24 on the expanded skirt 13 of the arm12. At the opposite end from the pivot point 24 is an eyelet 25 by meansof which a hook stick can be applied to open the fuse break lever to theposition shown in Fig. 3. Within the fuse break lever and pivotallyattached thereto at 26 is a fiip out arm 27. This flip out arm 27 isspring biased so that when the fuse link is severed within the fuse tubeeither from overload or upon opening the fuse break lever, an extrathrust action is applied to remove the fuse coil from the fuse tube.

The interior of the fuse break lever 1 is formed with channels tocontain and hold the conductor cable 28. The cable 28 is threadedbetween a wall 29 and the flip out lever 27 and around a finger 30extending angularly downward within the fuse break lever 1.

The use and operation of my invention are as follows:

The cable extending through the fuse tube has a fusible section whichdissolves upon overload. This fusible section is also slightly weakerand can be severed when a pull is exerted upon it. This pull istransmitted to the weak spot by a lever action on the cable. The end ofthe cable emerging from the fuse tube is threaded through the lever 1and around the flip out arm 27 while it is in the closed or in upwardposition as shown in Fig. 2. When it is desired to break the fuse linkin order to open the cutout under load, the lever 1 is pulled downwardlyto the position of Fig. 3. This downward thrust breaks the fuse linkwithin the fuse tube and as soon as the fuse link is severed the flipout arm 27 under spring pressure is released to spring downwardly andthus it quickly removes the free end of the cable from the fuse tube. Itis this quick action of the flip out arm in unison with the breakingaction on the fuse that prevents dangerous arcing or faulty load break.This manual means of opening a cutout during load is sturdy enough to beused when amperages in the vicinity of 100 are flowing through thecutout. The lever will not bend and the severing and removal action issufficiently decisive to prevent destruction or disaster.

I claim:

1. A fuse cutout including in combination spaced-apart line terminals,an insulating fuse tube having an open end, a fuse link in said tubecomprising a fusible element and a conducting leader and normallyelectrically connecting said line terminals, clamping means on said fusetube intermediate the ends thereof arranged for retaining the leader endof said fuse link, and a manually operable link-break lever pivotallymounted on one of said terminals adjacent the open end of said fuse tubeand having a manipulating means spaced laterally outwardly from saidtube, said lever being apertured to receive a looped portion of saidleader and including a flip out arm pivotally mounted thereon andengageable with said leader, said arm being biased for outwardrotational movement relative to said lever and away from said open endof said fuse tube.

2. A fuse cutout including in combination spaced-apart line terminals,an insulating fuse tube having an open end, a fuse link in said tubecomprising a fusible element and a conducting leader and normallyelectrically connecting said line terminals, clamping means on said fusetube intermediate the ends thereof arranged for retaining the leader endof said fuse link, and a manually operable link-break lever pivotallymounted on one of said terminals adjacent the open end of said fuse tubeand having a manipulating eyelet spaced laterally outwardly from saidtube, said lever being apertured and including a transverse integral webfor dividing said aperture into two chambers for receiving a loopedportion of said leader, and a flip out arm pivotally mounted on saidlever and engageable with said leader, said arm being biased for outwardrotational movement relative to said lever and away from said open endof said fuse tube.

References Cited in the file of this patent UNITED STATES PATENTS1,998,042 Boothe Apr. 16, 1935 2,154,688 Matthews et al Apr. 18, 19392,269,135 Tate Ian. 6, 1942 2,310,466 Schultz et a1 Feb. 9, 19432,323,213 Garrison June 29, 1943 2,324,044 Triplett et a1 July 13, 19432,409,077 Steinrnayer Oct; 8, 1946 2,460,967 Amundsen Feb. 8, 19492,637,795 Hubbard May 5, 1953 FOREIGN PATENTS 30,630 Australia Apr. 23,1931

